Abeni Barira Azeez, Frank-Peterside Nnenna, Otokunefor Kome
Department of Microbiology, Faculty of Science, University of Port Harcourt, Port Harcourt, Nigeria.
Access Microbiol. 2024 Jul 25;6(7). doi: 10.1099/acmi.0.000776.v6. eCollection 2024.
Traditionally, the presence of virulence features has been thought to be a key factor in differentiating pathogenic from commensal strains. An understanding of the virulence potential of isolates from various sources is essential to shed light on potential contamination/transmission rates between the various sources. This study was therefore aimed at exploring the occurrence of specific virulence genes and gene profiles associated with from human and non-human sources in Rivers State, Nigeria. Two hundred samples from human (urine and faeces) and non-human (soil and poultry droppings) sources (50 each) were analysed using standard microbiological procedures. DNA was extracted from isolates presumptively identified as using the Presto Mini gDNA Bacteria-Kit Quick protocol following the manufacturer's instructions. Isolate identities were confirmed using -specific 16S rRNA primers, and confirmed isolates were screened for the presence of six virulence genes [afimbriae binding adhesin (), type 1 fimbriae () and P-fimbrial usher protein ()], iron acquisition systems: obactin (), cytotoxic necrotizing factor I () and alpha-hemolysin (). Results showed that all isolates harboured at least one of the tested virulence genes, with (97%) as the most prevalent virulence gene and the least commonly occurring (35%). A higher occurrence of virulence genes was noted in non-human isolates, though and were not detected at all in any of the isolates studied (0%). Ten different profiles were observed with the profile the most commonly occurring virulence gene profile being in general (33.3%). For non-human isolates, however, was the most commonly occurring profile (42.9%). This study shows that the test from human and non-human sources do not carry distinct virulence gene profiles. Studies on a larger subset of isolates would however be necessary to determine if the virulence genes tested in this study really cannot be used to tell whether an isolate is from a human source or not in the South-South of Nigeria.
传统上，毒力特征的存在一直被认为是区分致病菌株和共生菌株的关键因素。了解来自各种来源的分离株的毒力潜力对于阐明不同来源之间的潜在污染/传播率至关重要。因此，本研究旨在探索尼日利亚河流州人类和非人类来源中与特定毒力基因及基因谱相关的情况。使用标准微生物学程序对来自人类（尿液和粪便）和非人类（土壤和家禽粪便）来源的200个样本（各50个）进行了分析。按照制造商的说明，使用Presto Mini gDNA Bacteria-Kit Quick协议从初步鉴定为的分离株中提取DNA。使用特异性16S rRNA引物确认分离株的身份，并对确认的分离株筛选六个毒力基因的存在情况[无纤毛结合黏附素（）、1型纤毛（）和P-纤毛导 usher蛋白（）]、铁获取系统：奥布菌素（）、细胞毒性坏死因子I（）和α-溶血素（）。结果表明，所有分离株至少含有一种测试的毒力基因，其中（97%）是最普遍的毒力基因，而最不常见（35%）。在非人类分离株中观察到毒力基因的发生率较高，尽管在所研究的任何分离株中均未检测到和（0%）。观察到十种不同的谱型，其中谱型是最常见的毒力基因谱型，总体上占（33.3%）。然而，对于非人类分离株，是最常见的谱型（42.9%）。本研究表明，来自人类和非人类来源的测试不携带明显不同的毒力基因谱型。然而，有必要对更大的分离株子集进行研究，以确定本研究中测试的毒力基因是否真的不能用于判断分离株是否来自尼日利亚南南地区的人类来源。
